Unlike corridor service, where adding a second daily service really seems to improve ridership, LD routes with a myriad of other options seem like relatively poor places to double up on service. Yes, Southern Pines loses the one seat ride to Philly and NYC, but if that's super important they can drive to Cary instead for the Carolinian, or transfer in DC. And they gain a one seat ride (very probably) to Chicago and points in between. That's actually a big boost to Raleigh and Richmond, for example - previously not only did you need to connect in DC, but the timing was too tight for a guaranteed connection. I seriously don't think the Northeast Corridor is hurting for rail service, and with the lemon of reduced capacity I think this is one of the better available ways to squeeze some lemonade out of it.
And even if it's a dismal failure operationally, it's Amtrak trying something different, attempting to improve their LD system with the resources they have and within the restrictions they have. They need to be attempting stuff like this, creating new connections within the network, looking for operational efficiencies in changing circumstances.